dom/media/ADTSDemuxer.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef ADTS_DEMUXER_H_
   8 #define ADTS_DEMUXER_H_
   9
  10 #include "mozilla/Attributes.h"
  11 #include "mozilla/Maybe.h"
  12 #include "MediaDataDemuxer.h"
  13 #include "MediaResource.h"
  14 #include "Adts.h"
  15
  16 namespace mozilla {
  17
  18 class ADTSTrackDemuxer;
  19
  20 DDLoggedTypeDeclNameAndBase(ADTSDemuxer, MediaDataDemuxer);
  21
  22 class ADTSDemuxer : public MediaDataDemuxer,
  23                     public DecoderDoctorLifeLogger<ADTSDemuxer> {
  24  public:
  25   // MediaDataDemuxer interface.
  26   explicit ADTSDemuxer(MediaResource* aSource);
  27   RefPtr<InitPromise> Init() override;
  28   uint32_t GetNumberTracks(TrackInfo::TrackType aType) const override;
  29   already_AddRefed<MediaTrackDemuxer> GetTrackDemuxer(
  30       TrackInfo::TrackType aType, uint32_t aTrackNumber) override;
  31   bool IsSeekable() const override;
  32
  33   // Return true if a valid ADTS frame header could be found.
  34   static bool ADTSSniffer(const uint8_t* aData, const uint32_t aLength);
  35
  36  private:
  37   bool InitInternal();
  38
  39   RefPtr<MediaResource> mSource;
  40   RefPtr<ADTSTrackDemuxer> mTrackDemuxer;
  41 };
  42
  43 DDLoggedTypeNameAndBase(ADTSTrackDemuxer, MediaTrackDemuxer);
  44
  45 class ADTSTrackDemuxer : public MediaTrackDemuxer,
  46                          public DecoderDoctorLifeLogger<ADTSTrackDemuxer> {
  47  public:
  48   explicit ADTSTrackDemuxer(MediaResource* aSource);
  49
  50   // Initializes the track demuxer by reading the first frame for meta data.
  51   // Returns initialization success state.
  52   bool Init();
  53
  54   // Returns the total stream length if known, -1 otherwise.
  55   int64_t StreamLength() const;
  56
  57   // Returns the estimated stream duration, or a 0-duration if unknown.
  58   media::TimeUnit Duration() const;
  59
  60   // Returns the estimated duration up to the given frame number,
  61   // or a 0-duration if unknown.
  62   media::TimeUnit Duration(int64_t aNumFrames) const;
  63
  64   // MediaTrackDemuxer interface.
  65   UniquePtr<TrackInfo> GetInfo() const override;
  66   RefPtr<SeekPromise> Seek(const media::TimeUnit& aTime) override;
  67   RefPtr<SamplesPromise> GetSamples(int32_t aNumSamples = 1) override;
  68   void Reset() override;
  69   RefPtr<SkipAccessPointPromise> SkipToNextRandomAccessPoint(
  70       const media::TimeUnit& aTimeThreshold) override;
  71   int64_t GetResourceOffset() const override;
  72   media::TimeIntervals GetBuffered() override;
  73
  74  private:
  75   // Destructor.
  76   ~ADTSTrackDemuxer();
  77
  78   // Fast approximate seeking to given time.
  79   media::TimeUnit FastSeek(const media::TimeUnit& aTime);
  80
  81   // Seeks by scanning the stream up to the given time for more accurate
  82   // results.
  83   media::TimeUnit ScanUntil(const media::TimeUnit& aTime);
  84
  85   // Finds the next valid frame and returns its byte range.
  86   const ADTS::Frame& FindNextFrame(bool findFirstFrame = false);
  87
  88   // Skips the next frame given the provided byte range.
  89   bool SkipNextFrame(const ADTS::Frame& aFrame);
  90
  91   // Returns the next ADTS frame, if available.
  92   already_AddRefed<MediaRawData> GetNextFrame(const ADTS::Frame& aFrame);
  93
  94   // Updates post-read meta data.
  95   void UpdateState(const ADTS::Frame& aFrame);
  96
  97   // Returns the frame index for the given offset.
  98   int64_t FrameIndexFromOffset(uint64_t aOffset) const;
  99
 100   // Returns the frame index for the given time.
 101   int64_t FrameIndexFromTime(const media::TimeUnit& aTime) const;
 102
 103   // Reads aSize bytes into aBuffer from the source starting at aOffset.
 104   // Returns the actual size read.
 105   uint32_t Read(uint8_t* aBuffer, int64_t aOffset, int32_t aSize);
 106
 107   // Returns the average frame length derived from the previously parsed frames.
 108   double AverageFrameLength() const;
 109
 110   // The (hopefully) ADTS resource.
 111   MediaResourceIndex mSource;
 112
 113   // ADTS frame parser used to detect frames and extract side info.
 114   ADTS::FrameParser* mParser;
 115
 116   // Current byte offset in the source stream.
 117   uint64_t mOffset;
 118
 119   // Total parsed frames.
 120   uint64_t mNumParsedFrames;
 121
 122   // Current frame index.
 123   int64_t mFrameIndex;
 124
 125   // Sum of parsed frames' lengths in bytes.
 126   uint64_t mTotalFrameLen;
 127
 128   // Samples per frame metric derived from frame headers or 0 if none available.
 129   uint32_t mSamplesPerFrame;
 130
 131   // Samples per second metric derived from frame headers or 0 if none
 132   // available.
 133   uint32_t mSamplesPerSecond;
 134
 135   // Channel count derived from frame headers or 0 if none available.
 136   uint32_t mChannels;
 137
 138   // Audio track config info.
 139   UniquePtr<AudioInfo> mInfo;
 140
 141   // Amount of pre-roll time when seeking.
 142   // AAC encoder delay is by default 2112 audio frames.
 143   media::TimeUnit mPreRoll;
 144 };
 145
 146 }  // namespace mozilla
 147
 148 #endif  // !ADTS_DEMUXER_H_